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picture of bridge

View southeast (downstream right) toward PA 8, William Flinn Highway

photo of bridge photo of bridge photo of bridge
View southwest;
Builder's plate mounted on inside center of upstream wall;
Downstream wall with "GH03"

Allegheny County Bridge Number 3 Gourdhead Run

Duncan Av over Gourhead Run [Gourdhead Run]


USGS 7.5" Topo Quad - UTM Coordinates:
Glenshaw - Zone 17; 0588-4490
Duncan Av [Green Belt]

-- William Flinn Highway [PA 8]
-- Bassett La

-- Gourhead Run [Gourdhead Run]

Closed spandrel concrete arch;
Parapet walls: concrete formed modules

35 ft

TOTAL LENGTH (including longest elevated ramp):


1919, Allegheny County
James Graham Chalfant, County Engineer

During years surrounding 1900, Allegheny County, under the direction of County Engineer Charles Davis, was busy throughout the region building stone arch bridges of a simple and similar design. Typically, they featured parapets with rounded top and slightly enlarged parapet endcaps.

Beginning about 1910 -- after Chalfant assumed the position of County Engineer -- new county bridges of this size were being constructed solely in concrete using a design which mimicked the earlier stone arches. On a few of the concrete structures, a builder's plate identifies the bridge as having been constructed by Allegheny County and includes the stream name and date.

Several bridges of this design are found throughout Allegheny County, but usually without the builder's plate to confirm the date or the authority in charge of construction. The similar of design and construction seems to imply that they were all built by Allegheny County, and other sources state construction dates to about 1936. This arched design was phased out and replaced by simpler beam bridges.

The arch portion of the bridge seems reasonably intact, but the parapet walls are severely crumbling. Examination of the other bridges of this design show a similar pattern. The parapets appear to have been constructed by stacking a series of formed concrete modules. The modules were shaped to mimic the rounded caps found on County bridges designed by Davis. Each block seems to have weathered differently and the seams between them allowed further decay. The Old Butler Plank Rd bridge over Gourhead Run is possibly the best preserved example.

The closed spandrel walls and outer faces of the parapets have recessed panels which further echo the designs from the County's earlier stone arch bridges. The parapets are most similar to those created in stone for Merriman Rd over Big Sewickley Creek.

Allegheny County assigns its bridges with an ID number counting from a stream's outflow, sequentially upstream. Although this is the second bridge upstream from the point where Gourhead Run flows into Pine Creek, the bridge which carries the Old Butler Plank Road over the same stream was completed further upstream in 1914 and given the designation of Bridge Number 2. In 1919, Duncan Av replaced Naylor Av as the connection between Butler Plank Rd (soon after bypassed by William Flinn Highway) with the Old Butler Turnpike (Mt. Royal Blvd). The new bridge on Duncan Av was given the Number 3 designation.

Older maps (including the 1876 Hopkins map) show the name of this stream as Gourhead Run; more recent maps and records often list the name as "Gourdhead" or"Gourdehead." The Hopkins map shows the name of early settlers in the area having Scotch-Irish surnames: McCaslin, McCully, McClay, McNeal, and others (About 2/3 mile above this bridge, McCaslin's Run flows into Gourhead Run.). Curiosity about the name discrepency led to two possibilities. Named for the Gaelic word for goat, the River Gour flows into Loch Linnhe in the Highlands of Scotland. And the geological term "gour" refers to a formation found in caves and flowing streams. Where mineral-laden streams form small still pools, deposits may build up a raised rim of stone -- the rimstone is a "gour." It is possible, given the course of Gourhead Run through the limestone and other sedimentary rock layers, the early settlers recognized the formations. "Gour" is such an obscure word in either meaning; perhaps later mapmakers transcribed the name into something more recognizable.

Farther upstream on Gourhead Run, northwest of the intersection of Harts Run Rd and Rosanna Dr, the hill rising up is named "Gourhead Knob" on the 1876 map.

The 1876 map shows Naylor Av as the only road in this area connecting the Allegheny and Butler Plank Road (PA 8) and the Old Butler Turnpike (Mt. Royal Blvd). Duncan Av [Green Belt] was not built until later; Duncan Av crosses Gourhead Run a few hundred feet upstream from Naylor Av on an 1898 county-built girder bridge by Charles Davis.

The former importance of the connection at Naylor Rd may be inferred from the site of a toll house on the Butler Plank Rd just south of the intersection of Naylor Av on the right bank of Pine Creek.


field check; cited map; UK Ordnance Survey

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Introduction -- Nearby Structures

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Last modified: 15-Apr-2003

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